The aforementioned U.S. patent describes an ignition system in which one flank, typically the rising flank, of an ignition control signal determines the ON time of a switch controlling current flow through an ignition coil, and the trailing flank the OFF time instants, when ignition is to occur. This system works very well; it has been found, however, that variations in control signals derived from various types of transducers cause changes in the design values of the dwell angle of current flow, that is, the duration between ON time and OFF time of current flow through the coil. Further, at extremely high-speed operation, the control of the ON time instant becomes difficult due to the rapid sequence of ON and OFF control pulses. Stray pulses, or stray and undesired wave shapes derived from an inductive signal transducer also interfere under some operating conditions, particularly under high-speed operation, with operation of the system in accordance with design requirements.